If you had told 10-year-old me that Posh Spice would leave her Spice Girls days behind, marry one of the sexiest men alive, and go on to become a high-end fashion designer — and a really good one, at that — I never would have believed you. But with her precise construction, minimalist marvels, and eye for classic shapes, Victoria Beckham — who turns 40 on Thursday — has crafted a design label that’s not only found a home with A-list celebrities like Eva Longoria and Cameron Diaz, but has also gained the admiration of such hard-won fashion critics as Vogue editor in chief Anna Wintour. Still having a hard time taking the pop-star-turned-tastemaker seriously? These 14 celebrity red-carpet looks will have you changing you mind faster than you can pull out your old Spice Girls fan gear.